The sensory innervation of the larynx will be studied in the rhesus monkey and compared where possible to equivalent human autopsy tissue. The nature and distribution of sensory terminals within the mucosa as well as underlying joints and ligaments will be studied during embryonic and post-natal development. This study will concentrate on attempting to understand the sensory neural organization of the laryngeal as well as pharyngeal mechanisms that might be relevant to understanding the etiology and/or pathogenesis of the sudden infant death syndrome. The sequence of maturation of laryngeal sensory receptors will be compared with the sequence of maturation in oral as well as pharyngeal tissue in the rhesus monkey and equivalent areas of man.